Along with the development of radio access technologies, data transmission is transported at an increased rate, and both an increased number of subscribers and an improved transmission rate of subscriber data increasingly demand for the performance of network elements of a core network. Particularly, the Selected IP Traffic Offload (SIPTO) technology refers to technology to allow the core network to select for a User Equipment (UE) a gateway at the shortest distance from an attachment point of the UE thereby have a part of data flows of the UE enter a Packet Data Network (PDN) directly through the gateway. Since the selected IP traffic offload technology can offload a specific IP service through the gateway at the shortest distance from the attachment point of the UE to thereby save transmission resources of the core network, this technology is highly regarded by an increasing number of those skilled in the art.
An existing macro eNB-based selected IP traffic offload architecture is generally embodied as an existing LTE system architecture in which a PDN Gateway (P-GW) at the shortest distance from the geographical location of an attachment point of a UE is selected as an offload point, and all of data flows intended for a packet data network to be subjected to a selected IP traffic offload strategy are transported through the packet data network gateway without influencing normal core network traffic. The selected IP traffic offload is activated in the course of establishing a connection of the packet data network, and particularly a core network control node, i.e., a Mobility Management Entity (MME), determines from subscription data and an operator configuration whether the selected IP traffic offload can be activated. Moreover, in the macro eNB-based selected IP traffic offload architecture, a macro eNB can also perform the selected IP traffic offload through a Local Gateway (L-GW), that is, the selected IP traffic enters a local home or enterprise network through the local gateway.
Along with the development of technologies, it is desirable to have the selected IP traffic offload architecture also applicable to a Home (enhanced) NodeB (H(e)NB), so that selected IP traffic offloaded traffic enters the local home or enterprise network through a direct tunnel between the H(e)NB and a local gateway. When the UE requests through the H(e)NB a connection of the data packet network to be established, a local gateway associated with the H(e)NB is selected for the UE as its packet data network gateway if the selected IP traffic offload is allowed to be activated in the network.
A selected IP traffic offload connection is established in the scenario of an H(e)NB typically in such a way that the H(e)NB reports an address of a local gateway to a core network control node and the core network control node establishes a selected IP traffic offload connection for the UE directly with the reported address of the local gateway.
The H(e)NB can be arranged integrally to or separately from the local gateway. In an existing solution, when the H(e)NB is arranged integrally to the local gateway, the H(e)NB reports the address of the local gateway to the core network control node which in turn can establish a selected IP traffic offload connection for the UE directly with the address of the local gateway. On the contrary, when the H(e)NB is arranged separately from the local gateway, the core network control node has to obtain the address of the local gateway for a selected IP traffic offload connection through a Domain Name System (DNS). Since there are a large number of local gateways in a scenario with deployment of an H(e)NB, a considerable query burden may arise from inquiring the domain name system for the address of the local gateway.
In a subsequent improved solution, the H(e)NB shall report the address of a local gateway to the core network control node which in turn establishes a selected IP traffic offload connection regardless of whether the H(e)NB is arranged integrally to or separately from the local gateway. However, the local gateway may fail to connect to a requested access point because the selected IP traffic offload connection is established simply through Access Point Name (APN)-based access control.
Consequently in such a solution, when the core network control node establishes a selected IP traffic offload connection for the UE with the reported address of the local gateway, the local gateway will return information of a connection establishment failure if the local gateway fails to connect to the packet data network requested by the UE, resulting in a failure to establish a selected IP traffic offload connection and a consequential waste of signalling resource.